High temperature vessel internals



Aug- 2, 1966 K. A. DE GHETTO ETAL 3,264,068

HIGH TEMPERATURE VESSEL INTERNALS Original Filed May 24, 1962 NW@ WORN Y O OmOaOju viv/nv |vnvnv 1v :vAvAl A United States Patent O 3,264,068 HIGH TEMPERATURE VESSEL INTERNALS Kenneth A. De Ghetto, Livingston, and William P. Long, Chestertownship, NJ., and Shih-Yann Yeh, Bronx, N.Y., assignors to Foster Wheeler Corporation, New York, N.Y., a corporation of New York Continuation of application Ser. No. 197,353, May 24, 1962. This application June 1, 1964, Ser. No. 371,721 2 Claims. (Cl. 23-288) This application is a continuation of co-pending application Serial No. 197,353, filed May 24, 1962 and now abandoned.

This invention relates to high temperature vessels and more particularly to the internals for such vessels.

In the construction of high temperature vessels, the outer shell of the vessel is most often made from steel which can withstand only moderate temperature levels. The outer shell is therefore lined with a refractory insulating material. A metallic shroud is placed within the insulating liner but is spaced slightly inwardly from the lining. The space between the lining and the shroud permits expansion of the shroud and `also provides a passageway for the -hot fluid. Since the hot fluid is under pressure, the same fluid pressure exists on both sides of the shroud because of the passageway. The shroud which must be made of a heat resistant metal serves three important functions. First it prevents by-passing of the process stream around .the catalyst bed through t-he brick or castable refractory which would result in failure to meet process requirements and guarantees. Such failure would occur because some of thev gas would not contact the catalyst and therefore could not react. Secondly, the shroud prevents the hot gases from channeling through the brick to the vessel Wall resulting in hot spots which would raise the shell temperature above acceptable design specifications. Thirdly, for certain types of refractories the shroud prevents the pick-up of silica in the gas stream from the refractory. However, it is necessary that the shroud be welded to the shell to prevent by-passing.

The plate used in making the shroud must be thick enough to withstand the small differential pressure which exists across the shroud. Also, the shroud must be strong enough and flexible enough to withstand the -high ternperature gradient existing from vessel temperature to outside shell temperature. The attachment used to conneet the shroud to the `shell must be flexible enough to withstand the stress resulting from differential expansion between the shroud and the vessel.

In accordance with one aspect of this invention, the shroud is structurally supported by the refractory. In accordance with still another aspects, by-passing about the shroud is prevented by a thin bellows which does not require suiiicient dimension to give support to the shroud, but which still prevents the by-pass of gas around the outside of the shroud and minimizes heat conductivity from the shroud to the shell.

Therefore, it is an object of this invention to provide improved internals for high ltemperature vessels.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings in which:

FIGURE l is an elevational View partly in section of a vessel for conducting high temperature reactions and embodying this invention.

FIGURE 2 is `an enlarged detail in section showing the connection of the shroud to the shell.

Referring now to FIGURE l, a shell 1, which may be made of carbon steel or low alloy carbon steel, has a castable refractory 2, refractory brick 3, and packing 4, forming a lining 5 within its interior. The packing 4 is 3,264,068 Patented August 2, 1966 impregnated with `an insulating material. The shell 1 forms a chamber 7. Within chamber 7 high temperature operations occur as for example contacting a catalyst 6 with a hot fluid. The shell 1 is provided with an upper fluid opening 8 and a lower fluid opening 9. Hot uid may pass into the chamber 7 through the upper fluid opening 8 and then be discharged from. the chamber 7 by the lower fluid opening `9, after passing through the catalyst 6.

Since the lining 5 cannot withstand the extreme temperatures encountered in such a vessel, a shroud 11 is provided within the lining 5. The shroud 11 is spaced slightly inwardly from the lining 5 to provide an annular space 12. This space is necessary to allow for expan` sion of the shroud 11 and to permit the tiuid in the chamber 7 to exert the inlet pressure on the outside of the shroud 11. It must `be remembered that even a heat-resistant metal such as nickel-chromium steel alloy or a stainless steel undergoes `a loss of strengt-h at the temperatures involved in such a vessel. Therefore, it is often not desirable to have shroud 11 withstand the pressure of the fluid passing through the chamber 7. To overcome this, the top of annular space 12 is left open and fluid is allowed vto enter the annular space 12. In this way, the fluid exerts the inlet pressure on the outside of the shroud 11. Since the inlet pressure within the shroud is reduced by the fluid passing through the catalyst bed, the shroud must only withstand this differential pres# sure rather than the inlet pressure itself. If annular space 12 is sealed at both the top and bottom, the space 12 would have to be pressurized or else shroud 11 would have to be excessively massive.

Around the lower fluid opening 9 a collar 15 is placed. Collar 15 extends slightly upwardly into the chamber 7 substantially parallel to the lining 5. Between the collar 15 and the lining 5, a groove 20 is formed. The lower edge of the shroud 11 is located in the bottom of this groove 20 and against the collar 15. Bearing plates 18 are attached to the shroud 11 so as to be embedded in the lcollar 15. In this way the -weight of the shroud 11 receives all structural support from the refractory collar 15.

In order to prevent by-passing of the fluid around the catalyst 6, the lower edge of the shroud 11 must be sealed to the shell 1. In order to prevent heat conduction, a thin bellows is connected by a weld 16 to the lower edge of the shroud 11 and to the shell 1 by weld 17 which preferably is bimetallic. It is immaterial at what level shroud 11 is welded to shell 1, as long as it blocks the passage of gas from space 12 around the catalyst 6 in chamber 7. Besides being substantially thinner than the shroud 11, although preferably of the same material, the bellows 14 is corrugated. This not only permits expansion and contraction but `also creates an extended path t-o prevent heat conduction to the shell 1. Low heat conduction to shell 1 prevents a serious hot spot in shell 1 in the vicinity of the weld 17.

Surrounding the bellows 14 is an impregnated packing 4 which is yieldable to accommodate the deformation of the bellows 14. It is desirable -to employ packing with a fabric structure as the impregnated packing 4. The fabric weave is disposed transverse to the potential leakage path; so that in the event of failure of bellows 14. weld 16 and weld 17, the impregnated packing would serve as a seal.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by Way of example and that numerous changes in the details of construction and the combination and arrangements of parts may be resorted to without departing from the spirit and the scope of the A vessel comprising in combination:

an outer shell dening a chamber, said shell having a reduced upper end portion forming an upper fluid opening and a reduced lower end portion forming a lower 'fluid opening,

refractory insulating lining attached to the interior of said shell,

refractory insulating collar extending upwardly into said chamber from said lower fluid opening to form a groove between said collar and said lining, heat-resistant metallic shroud within said chamber and spaced slightly from said lining with the lower portion of said shroud against said collar whereby Huid pressure within said chamber is exerted both on the inside of said shroud and on the outside of said shroud substantially to the bottom of said shroud, said shroud having a lower edge located in said groove,

bearing plate extending from said shroud into said collar to support said shroud, and

a bellows embedded in said refractory lining and having an upper edge and a lower edge, said upper edge being welded to said shroud and said lower edge welded to said shell, said bellows being substantially thinner than said shroud and corrugated to limit heat conduction between said shroud and said shell and to permit expansion and contraction.

. A vessel comprising in combination:

steel outer shell defining a chamber, said shell having a reduced upper end portion forming a uid inlet and a reduced lower end portion forming a uid outlet,

4 refractory insulating lining attached to ther interior of said shell, refractory insulating collar extending upwardly into said chamber from 4said fluid outlet to form a groove between said collar and said lining, cylindrical heat-resistant metallic shroud within said chamber and spaced slightly from said lining with the lower portion of said shroud against said collar whereby fluid pressure within said chamber is exerted both on the inside of said shroud and on the outside of said shroud substantially to the bottom of said shroud, said shroud having a lower edge located in said groove, bearing plate extending from said shroud into said collar to support said shroud, and bellows embedded in said refractory lining and having an upper edge and a lower edge, said upper edge being welded to said shroud and said lower edge being welded to said shell, said bellows being substantially thinner than said shroud to limit heat conduction from said shroud to said shell and being corrugated to permit expansion and contraction.

References Cited by the Examiner UNITED STATES PATENTS 1,478,550 12/1923 Casale 23-289 2,548,519 4/1951 Cummings 23-288 2,572,338 10/1951 Hartwig et al 23-284 2,683,654 7/1954 Bergman 23-288 2,973,252 2/1961 Shields et al. 23--288 MORRIS O. WOLK, Prima/y Examiner.

35 JOSEPH SCOVRONEK, Emmi/zeri 

1. A VESSEL COMPRISING IN COMBINATION: AN OUTER SHELL DEFINING A CHAMBER, SAID SHELL HAVING A REDUCED UPPER END PORTION FORMING AN UPPER FLUID OPENING AND A REDUCED LOWER END PORTION FORMING A LOWER FLUID OPENING, A REFRACTORY INSULATING LINING ATTACHED TO THE INTERIOR OF SAID SHELL, A REFRACTORY INSULATING COLLAR EXTENDING UPWARDLY INTO SAID CHAMBER FROM SAID LOWER FLUID OPENING TO FORM A GROOVE BETWEEN SAID COLLAR AND SAID LINING, A HEAT-RESISTANT METALLIC SHROUD WITHIN SAID CHAMBER AND SPACED SLIGHTLY FROM SAID LINING WITH THE LOWER PORTION OF SAID SHROUD AGAINST SAID COLLAR WHEREBY FLUID PRESSURE WITHIN SAID CHAMBER IS EXERTED BOTH ON THE INSIDE OF SAID SHROUD AND ON THE OUTSIDE OF SAID SHROUD SUNSTANTIALLY TO THE BOTTOM OF SAID SHROUD, SAID SHROUD HAVING A LOWER EDGE LOCATED IN SAID GROVE, 